Question: Simplify the following expression: $n = \dfrac{5p}{7} + \dfrac{p}{9}$
Explanation: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $7$ and $9$ $\lcm(7, 9) = 63$ $ n = \dfrac{9}{9} \cdot \dfrac{5p}{7} + \dfrac{7}{7} \cdot \dfrac{p}{9} $ $n = \dfrac{45p}{63} + \dfrac{7p}{63}$ $n = \dfrac{45p +7p}{63}$ $n = \dfrac{52p}{63}$